Gov. Jerry Brown's planned special election in June asking voters to extend three state taxes could be an exclusively vote-by-mail ballot.

If the idea being batted around takes off, it would be a first for California.

The governor stated during his State of the State address Monday that he wants a "clear mandate" from the public for his plan, but he's also looking at his best chances of winning. And some advisers figure a mail vote would give him that chance.

Those over 55, on the other hand, favored five-year extensions of increases in the state personal income tax, sales tax and vehicle license fee by 56 percent to 38 percent.

Older voters are also the most likely to vote by mail.

A mail-in ballot could save counties millions of dollars in election costs. But there is a risk - disenfranchising voters in Democratic and minority-heavy Los Angeles County, where mail delivery is unreliable in spots and 71 percent of voters still cast ballots at their neighborhood precincts.

Steve Glazer, the governor's political adviser, sidestepped the possibility of a June vote-by-mail election, saying only that "step one is for the Legislature to adopt his tough budget cuts."

There is a catch, however.

Just as it would take two-thirds of the Legislature to authorize a special election, it would take a two-thirds majority to approve the vote-by-mail format.

In both cases, Brown will need Republican support.

Staffing surprise: Oakland Mayor Jean Quanwent into Monday's news conference about police issues to announce the city was hiring back 10 laid-off cops for its understaffed department.

By the time she left, the number had jumped to 39.

In the process, Quan left everyone wondering how a city that supposedly is so broke that it had to lay off 80 officers last summer is suddenly flush with cash.

Here's the story.

The Oakland PD has gone from a high of 837 officers in 2008 to 656 today. For next fiscal year, which starts July 1, it is budgeted to have just 637 officers.

The staffing declines and fear of future layoffs have caused an avalanche of officer retirements and moves to other police departments.

As a result, budget crunchers figured that even if they hired back 10 cops - temporarily bringing the force to 666 officers - attrition would still drop the department back down to the budgeted 637 or lower by July.

Even Steven.

But then, while answering questions from reporters Monday, Quan upped the ante, declaring that the department's staffing baseline would continue at the higher 666 officers - which would require bringing back a total of 39 cops.

It might also mean an extra $5 million a year.

City Administrator Dan Lindheim, who had quickly done the math in his head, hinted to reporters that Quan might have misspoken.

The mayor, however, remained firm, telling The Chronicle's Matthai Kuruvila after the news conference that while the 666 level was "aggressive," the city would find the money.